1. Field of Invention
The invention relates to an adjusting method, and particularly relates to a method for adjusting a contrast value of a video image.
2. Description of Related Art
A contrast value is a property of a video image, defined as the ratio of the luminance of the brightest color (white) to that of the darkest color (black) in the video image. A high contrast ratio is a desired aspect of any display.
Typically, a software adjusting method is used to adjust the contrast value of a video image to improve display quality. However, when a video image has a lower contrast ratio, even though software is used to adjust the contrast value of the video image, the adjustment result usually cannot meet the requirement because the content information of the original video image is not enough. For example, for the darker region in the video image, even though the software is used to adjust the darker region to have a highest contrast value, a lot of content information still miss in the final display result because the original video image data does not contain these content information. Therefore, another method of directly adjusting the contrast value of the video capturing end is provided. However, in such method, the eyes of human are used to determine the adjustment result of the contrast value. Therefore, the adjustment result is not always correct. In other words, it is very difficult to use the above methods to improve the contrast value.